Ok, here are some shots of NSW tunnels from the internet.
Woy Woy, showing how the catenary wire is brought down closer to the contact wire
From the outside
Glebe Tunnel. Light rail now, but shows how the wires are often strung side-by-side
Glenbrook. Very good at showing the height difference of the wires
Glenbrook again
Woy Woy again? Gives an idea of the tunnel dimensions
The Zig Zag tunnels. Another good shot for modellers
And lastly, a shot to show the dimensions compared to the XPT passing through
Hope that helps.
Woy Woy, showing how the catenary wire is brought down closer to the contact wire
From the outside
Glebe Tunnel. Light rail now, but shows how the wires are often strung side-by-side
Glenbrook. Very good at showing the height difference of the wires
Glenbrook again
Woy Woy again? Gives an idea of the tunnel dimensions
The Zig Zag tunnels. Another good shot for modellers
And lastly, a shot to show the dimensions compared to the XPT passing through
Hope that helps.